1. Field of the Invention
The present invention is directed to iron promoted vanadium antimony oxide catalyst useful in the ammoxidation of a C3-C5 paraffinic hydrocarbon to its corresponding α-β-unsaturated nitrile ammoxidation of propylene with NH3 and oxygen to acrylonitrile, ammoxidation of methylpyridine with NH3 and oxygen to make cyanopyridine, the ammoxidation of m-xylene with NH3 and oxygen to make isophthalonitrile and the oxidation of o-xylene to make phthalic anhydride. In particular, the present invention is directed to a process for the manufacture of an iron promoted vanadium antimony oxide catalyst useful in the ammoxidation of propane to acrylonitrile. More specifically, the instant invention relates to the preparation of an improved iron promoted vanadium antimony catalyst resulting from a catalyst preparation which utilizes a source of iron (i.e. an iron containing compound such as Fe2O3) having a BET surface area greater than about 120 m2/gram.
2. Description of the Prior Art
Commercial processes for the production of acrylonitrile employ propylene as a feedstock. However, because of the price differential between propylene and propane, an economic incentive exists for the development of a commercial process for the ammoxidation of propane to acrylonitrile. The development of such a process depends upon a viable catalyst useful for the conversion of propane to acrylonitrile.
Vanadium antimony type catalysts useful in the ammoxidation of propane to acrylonitrile along with various methods of making such catalysts are taught in the following U.S. Pat. Nos. 6,083,869; 5,994,259; 5,866,502; 5,498,588; 5,332,855; 5,258,543; 5,214,016; 5,008,427; 4,788,317; 4,784,979; 4,746,641; 3,860,534; and 3,681,421.
Many of these patents (e.g. U.S. Pat. Nos. 5;994,259; 5,498,588; 5,008,427) teach iron as an additional (sometimes optional) promoter for vanadium antimony type catalysts. The source of such iron was typically iron oxide (Fe2O3) which was obtained from commercial sources and consisted of large agglomerated particles of the iron oxide. Such compounds typically have a BET surface area of less than about 100 m2/gram.